A touch version can have all the same features as the PC version, but if the gameplay suffers because of UI limitations, then the game suffers. If it takes 3 touch actions to do the same thing that one right-click can accomplish, that can have a significant impact on whether management tasks are fun. Or not. It depends on the UI and the gameplay.To clarify, though, I did not say the gameplay didn't suffer upon moving it to mobile. I said the gameplay of the original game on the PC platform, having not being altered in the slightest, would not be affected. You wouldn't be using touch-and-drag on the PC version of the game, would you?
Designing good game UI is hard, and the fewer tools you have, the harder it becomes.
I never played the tablet version of Civ V, so I'll have to ask: Civ V PC relies a lot on on-hover tooltips to convey much of the information that the player needs. How does the touch version handle this, since on-hover is not possible in a touch interface?